Chinese Physics C

Cosmic Implications of $ {^{12}\boldsymbol C(\boldsymbol n,\bf\gamma)^{13}\boldsymbol C }$ Reaction: A Nuclear Astrophysical Perspective

Soumya Saha

Published:

Abstract:
We have studied a comprehensive work on the neutron capture cross section for

\begin{document}$ ^{12}\mathrm C $\end{document}

within the relevant astrophysical energy range. Through rigorous R-matrix analysis, we have determined the Maxwellian-averaged cross section to be 11.98

\begin{document}$ \pm $\end{document}

0.25 μb at kT=30 keV. This result is about 4 times higher than the thermal neutron capture cross section estimated in the earlier works assuming a

\begin{document}$ \dfrac{1}{v} $\end{document}

law. The implications of our findings extend to the region of inhomogeneous big-bang models in nuclear astrophysics, where understanding the behaviour of neutron capture cross sections plays a crucial role in elucidating the intricate processes that shaped the early universe.

Dynamics of ⁷Li Breakup and its Influence on Elastic Scattering: A Study of ⁷Li + ¹⁴⁴Sm System

A. Morzabayev, N. Amangeldi, Awad A. Ibraheem, D. Soldatkhan, G. Yergaliuly, B. Mauyey, A. Orazalievna, Sh. Hamada

Published:

Abstract:
The angular distributions of ⁷Li + ¹⁴⁴Sm elastic scattering over the energy range of 21.6–52 MeV are reanalyzed utilizing various interaction potentials. The analysis seeks to probe the consistency of the implemented potentials in representing the considered data and investigate the cluster nature of the weakly bound ⁷Li projectile to better understand the impacts of ⁷Li breakup on the elastic scattering channel. Strong coupling to the breakup channel has a substantial impact on elastic data and reproduces a repulsive dynamical polarization potential, which drastically diminishes the real potential strength. This reported impact was simulated by introducing a semi-microscopic repulsive DPP and by implementing the method of continuum discretized coupled channels. The analysis is also extended to check the impact of triton transfer on the elastic scattering data.

Interaction of photons with silver and indium nuclei at energies up to 20 MeV

J. H. Khushvaktov, M. A. Demichev, D. L. Demin, S. A. Evseev, M. I. Gostkin, V. V. Kobets, F. A. Rasulova, S. V. Rozov, E. T. Ruziev, A. A. Solnyshkin, T. N. Tran, E. A. Yakushev, B. S. Yuldashev

Published:

Abstract:
The yields of photonuclear reactions in the ¹⁰⁷Ag, ¹¹³In, and ¹¹⁵In nuclei have been measured. Monte Carlo simulations have been performed using the Geant4 code, and the results have been compared with the experimental ones. The isomeric ratios of the yields in the reactions ¹⁰⁷Ag(γ,n)^106m,gAg and ¹¹³In(γ,n)^112m,gIn have been determined. The cross sections for the reactions ¹⁰⁷Ag(γ,n)^106gAg and ¹⁰⁷Ag(γ,2n)¹⁰⁵Ag at an energy of 20 MeV have been calculated on the basis of the experimental data.

Analysis of the data for γp → f₁(1285)p photoproduction

Ai-Chao Wang, Neng-Chang Wei, Fei Huang

Published:

Abstract:
The photoproduction of

\begin{document}$ f_1(1285) $\end{document}

meson off proton is investigated within an effective Lagrangian approach. The t-channel ρ- and ω-exchange diagrams, u-channel nucleon-exchange diagram, generalized contact term, and s-channel pole diagrams of nucleon and a minimal number of nucleon resonances are taken into account in constructing the reaction amplitudes to describe the experimental data. Three different models, i.e., the Feynman model, the Regge model, and the interpolated Regge model, are employed where the t-channel reaction amplitudes are constructed in Feynman type, Regge type, and interpolated Regge type, respectively. The results show that in neither Feynman model with two nucleon resonances nor interpolated Regge model with one nucleon resonance can the available data for

\begin{document}$ \gamma p \to f_1(1285) p $\end{document}

be satisfactorily reproduced. Nevertheless, in the Regge model, when any one of the

\begin{document}$ N(1990){7/2}^+ $\end{document}

,

\begin{document}$ N(2000){5/2}^+ $\end{document}

,

\begin{document}$ N(2040){3/2}^+ $\end{document}

,

\begin{document}$ N(2060){5/2}^- $\end{document}

,

\begin{document}$ N(2100){1/2}^+ $\end{document}

,

\begin{document}$ N(2120){3/2}^- $\end{document}

,

\begin{document}$ N(2190){7/2}^- $\end{document}

,

\begin{document}$ N(2300){1/2}^+ $\end{document}

, and

\begin{document}$ N(2570){5/2}^- $\end{document}

resonances is considered, the data can be well described. The resulted resonance parameters are consistent with those advocated in Particle Data Group (PDG) review. Further analysis shows that in high-energy region, the peaks of

\begin{document}$ \gamma p \to f_1(1285) p $\end{document}

differential cross sections at forward angles are dominated by the contributions from t-channel ρ- and ω-exchange diagrams, while in low-energy region, the s-channel pole diagrams of resonances also provide significant contributions to the

\begin{document}$ \gamma p \to f_1(1285) p $\end{document}

cross sections.

Investigation of ⁵⁸Ni (n, p)⁵⁸Co reaction cross-section with covariance analysis

Akash Hingu, S. Mukherjee, Siddharth Parashari, Sangeeta, A. Gandhi, Mahima Upadhyay, Mahesh Choudhary, Sumit Bamal, Namrata Singh, G. Mishra, Sukanya De, Saurav Sood, Sajin Prasad, G. Saxena, Ajay Kumar, R.G. Thomas, B.K. Agrawal, K. Katovsky, A. Kumar

Published:

Abstract:
The excitation function of the

\begin{document}$ {}^{58}{\rm{Ni}} (n, p){}^{58}{\rm {Co}} $\end{document}

reaction is measured by using the well-established neutron activation technique and γ-ray spectroscopy. Neutrons in the energy range of 1.7 to 2.7

\begin{document}$ \rm MeV $\end{document}

were generated using the

\begin{document}$ ^{7}{\rm{Li}}(p, n) $\end{document}

reaction. The neutron flux was measured by using the standard

\begin{document}$ {}^{115}{\rm{In}} (n, n'){}^{115{\rm m}}{\rm{In}} $\end{document}

monitor reaction. The results of neutron spectrum averaged cross-section of

\begin{document}$ {}^{58}{\rm{Ni}} (n, p){}^{58}{\rm{Co}} $\end{document}

reactions are compared with existing cross-section data available in the EXFOR data library as well as with various evaluated data libraries like ENDF/B-VIII.0, JEFF-3.3, JENDL-4.0 and CENDL-3.2. Theoretical calculations were performed using the nuclear reaction code TALYS. Various nuclear level density (NLD) models were tested and compared with the present findings. Realistic NLDs are also obtained through the spectral distribution method (SDM). The cross-section results are reported along with the absolute errors by investigating uncertainty propagation, using the covariance technique. The corrections for γ-ray true coincidence summing, low-energy background neutrons and γ-ray self attenuation are performed. The experimental cross-section obtained in the present study is consistent with previously published experimental data, evaluated libraries and theoretical calculations carried out using the TALYS code.

Resonant contribution of the three-body decay process $ {\bar B}_{s} \rightarrow K^{+}K^{-} P $ in perturbation QCD

Gang Lü, Chang Chang Zhang, Yan-Lin Zhao, Li-Ying Zhang

Published:

Abstract:
We investigate the CP violation in the decay process

\begin{document}$ \bar B_{s} \rightarrow \phi(\rho,\omega) P \rightarrow K^{+}K^{-}P $\end{document}

by considering the interference effects of

\begin{document}$ \phi\rightarrow K^{+}K^{-} $\end{document}

,

\begin{document}$ \rho\rightarrow K^{+}K^{-} $\end{document}

and

\begin{document}$ \omega\rightarrow K^{+}K^{-} $\end{document}

within the framework of perturbative QCD method (P refers to π, K, η and

\begin{document}$ \eta' $\end{document}

pseudoscalar mesons, respectively). We analyse the mixings of

\begin{document}$ \phi-\rho^{0} $\end{document}

,

\begin{document}$ \phi-\omega $\end{document}

and

\begin{document}$ \omega-\rho^{0} $\end{document}

and provide the amplitudes of the quasi-two-body decay processes. The CP violation for

\begin{document}$ \bar B_{s} \rightarrow K^{+}K^{-} P $\end{document}

decay process is obvious at the ranges of the three vector mesons interferences. Meanwhile, the localised CP violation can be found for comparing with the experiment results from three-body decay process at the LHC in the near future.

Thermal analysis and Joule-Thomson expansion of black hole exhibiting metric-affine gravity

Muhammad Yasir, Tiecheng Xia, Faisal Javed, G. Mustafa

Published:

Abstract:
This study examines a recently hypothesized black hole, which is a perfect solution of metric-affine gravity with a positive cosmological constant, and its thermodynamic features as well as the Joule-Thomson expansion. We develop some thermodynamical quantities, such as volume, Gibbs free energy, and heat capacity, using the entropy and Hawking temperature. We also examine the first law of thermodynamics and thermal fluctuations, which might eliminate certain black hole instabilities. In this regard, a phase transition from unstable to stable is conceivable when the first law order corrections are present. Besides that, we study the efficiency of this system as a heat engine and the effect of metric-affine gravity for physical parameters

\begin{document}$ q_e $\end{document}

,

\begin{document}$ q_m $\end{document}

,

\begin{document}$ \kappa_{\mathrm{s}} $\end{document}

,

\begin{document}$ \kappa_{\mathrm{d}} $\end{document}

and

\begin{document}$ \kappa_{\mathrm{sh}} $\end{document}

. Further, we study the Joule-Thomson coefficient, and the inversion temperature and also observed the isenthalpic curves in the

\begin{document}$ T_i -P_i $\end{document}

plane. In metric-affine gravity, a comparison is made between the Van der Waals fluid and the black hole to study their similarities and differences.

Jet modification in absence of QGP-medium: the role of multiparton interactions and color reconnection

Prottoy Das, Abhi Modak, Debjani Banerjee, Rathijit Biswas, Supriya Das, Sanjay K. Ghosh, Sibaji Raha, Sidharth Kumar Prasad

Published:

Abstract:
Recent studies of high-multiplicity events in small collision systems (proton-proton and proton-lead) have drawn research interest towards the possibility of the formation of partonic medium in such systems. One of the important consequences of the formation of dense partonic medium is quenching of high-momentum final-state particles resulting in several experimental observations such as suppression in nuclear modification factor

\begin{document}$ R_{\rm AA} $\end{document}

, modification of jet shape observable

\begin{document}$ \rho(r) $\end{document}

and jet fragmentation (

\begin{document}$ z^{\rm ch} $\end{document}

) distributions, etc. In this work, we study

\begin{document}$ \rho(r) $\end{document}

and

\begin{document}$ z^{\rm ch} $\end{document}

for inclusive charged-particle jets in proton-proton (pp) collisions at

\begin{document}$ \sqrt{s} $\end{document}

= 13 TeV using PYTHIA 8 Monash 2013 Monte Carlo simulation. We show that the color reconnection (CR) and multiparton interaction (MPI) mechanisms in PYTHIA 8 can lead to an increased rate of jet production. We also find that the mechanisms of MPI and CR and change in the gluonic contribution in high-multiplicity events result in significant modification of

\begin{document}$ \rho(r) $\end{document}

and

\begin{document}$ z^{\rm ch} $\end{document}

compared to those in minimum bias events for 10

\begin{document}$ <p_{\rm T,\,jet}^{\rm ch}< $\end{document}

20 GeV/c. We notice a direct connection of

\begin{document}$ \langle N_{\rm MPI}\rangle $\end{document}

and gluonic contribution with the amount of modification in

\begin{document}$ \rho(r) $\end{document}

– the larger the number of MPIs and/or gluonic contribution, the larger the amount of modification of

\begin{document}$ \rho(r) $\end{document}

.

Strong gravitational lensing of blazar gamma-radiation and intergalactic magnetic fields

Yu.N. Eroshenko

Published:

Abstract:
The influence of intergalactic magnetic fields on the strong gravitational lensing of blazar secondary gamma radiation is discussed. Currently, two cases of strong gravitational lensing of blazar gamma-radiation are known, where radiation is deflected by galaxies on the line of sight between the blazars and the Earth. The magnetic field can affect the movements of electron-positron pairs generated by primary radiation, and thereby change the directions of secondary gamma radiation. It modifies the equation of the gravitational lens and leads to the dependence of the observed signal in the secondary gamma radiation on the energy of photons and on the magnetic field. Accordingly, it is possible in principle to estimate the intergalactic magnetic fields from the time delay of signals, from the angular position of images (for future high-resolution gamma-ray telescopes) or from the shape of the observed energy spectrum. This method is demonstrated by the example of the blazar B0218+357. In this case however it is not possible to obtain useful constraints due to the large distances to the blazar and the lens galaxy. The result is only a lower limit on the magnetic field

\begin{document}$ B>2\times10^{-17} $\end{document}

G, which is weaker than other existing constraints. But the future discoveries of lensed blazars may provide more favourable opportunities for measuring the magnetic fields, especially with the help of new generation of gamma-ray telescopes such as e-ASTROGAM, GECAM, and SVOM as well as future gamma-ray telescopes with high angular resolution,

\begin{document}$ \sim0.1''$\end{document}

.

Further monopole effects in neutron-rich Sb isotopes

Han-Kui Wang, Y. L. Sun, B. W. Jiang, F. F. Zeng, M. L. Liu

Published:

Abstract:
The level spectra of neutron-rich Sb isotopes have been investigated within a shell-model space containing cross-shell excitations and the intruder orbit

\begin{document}$ i_{13/2} $\end{document}

. High-spin levels (27/2

\begin{document}$ ^- $\end{document}

) and (29/2

\begin{document}$ ^- $\end{document}

) in

\begin{document}$ ^{135} $\end{document}

Sb are taken over by monopole effect induced by the orbit

\begin{document}$ i_{13/2} $\end{document}

. The ground state and excited levels in

\begin{document}$ ^{136} $\end{document}

Sb are well improved by considering monopole correction between neutron orbits

\begin{document}$ f_{7/2} $\end{document}

and

\begin{document}$ h_{9/2} $\end{document}

. The energy shrinking of the first excited state 5/2

\begin{document}$ ^+ $\end{document}

in

\begin{document}$ ^{135,137} $\end{document}

Sb isotopes is explained by the

\begin{document}$ \pi d_{5/2} $\end{document}

shift due to the attractive

\begin{document}$ \pi d_{5/2} \nu f_{7/2} $\end{document}

monopole interaction when more and more neutrons occupy the orbit

\begin{document}$ f_{7/2} $\end{document}

. The ground state of

\begin{document}$ ^{139} $\end{document}

Sb is predicted as 5/2

\begin{document}$ ^+ $\end{document}

: due to the shrinking of states 5/2

\begin{document}$ ^+ $\end{document}

in Sb isotopes that causes ground state inversion when N = 88. These further monopole effects extend the applicable range of present Hamiltonian to nuclei with more neutrons above N = 82 shell. This Hamiltonian will be public and welcome to contact authors.

Evolution of N = 20, 28, 50 shell closures in the 20 ≤ Z ≤ 30 region in deformed relativistic Hartree-Bogoliubov theory in continuum

Ru-You Zheng, Xiang-Xiang Sun, Guo-fang Shen, Li-Sheng Geng

Published:

Abstract:
Magicity, or shell closure, plays an important role in our understanding of complex nuclear phenomena. In this work, we employ one of the state-of-the-art density functional theories, the deformed relativistic Hartree-Bogoliubov theory in continuum (DRHBc) with the density functional PC-PK1, to investigate the evolution of the

\begin{document}$ N=20,28,50 $\end{document}

shell closures in the

\begin{document}$ 20 \leqslant Z \leqslant 30 $\end{document}

region. We show how these three conventional shell closures evolve from the proton drip line to the neutron drip line by studying the charge radii, two-neutron separation energies, two-neutron gaps, quadrupole deformations, and single-particle levels. In particular, we find that in the

\begin{document}$ 21 \leqslant Z \leqslant 27 $\end{document}

region, the

\begin{document}$ N=50 $\end{document}

shell closure disappears or becomes quenched, mainly due to the deformation effects. Similarly, both experimental data and theoretical predictions indicate that the

\begin{document}$ N=28 $\end{document}

shell closure disappears in the Mn isotopic chain, also predominantly due to the deformation effects. The DRHBc theory predicts the existence of the

\begin{document}$ N=20 $\end{document}

shell closure in the Ca, Sc, and Ti isotopic chains, but the existing data for the Ti isotopes suggests the contrary, and therefore more investigations are needed.

Nuclear mass predictions based on deep neural network and finite-range droplet model (2012)

To Chung Yiu, Haozhao Liang, Jenny Lee

Published:

Abstract:
A neural network with two hidden layers is developed for nuclear mass prediction, based on the finite-range droplet model (FRDM12). Different hyperparameters, including the number of hidden units, the choice of activation functions, the initializers, and the learning rates, are adjusted explicitly and systematically. The resulting mass predictions are achieved by averaging the predictions given by several different sets of hyperparameters with different regularizers and seed numbers. It can provide us not only the average values of mass predictions but also reliable estimations in the mass prediction uncertainties. The overall root-mean-square deviations of nuclear mass have been reduced from 0.603 MeV for the FRDM12 model to 0.200 MeV and 0.232 MeV for the training set and validation set, respectively.

Gauss-Bonnet solution with a cloud of strings in de Sitter and anti-de Sitter space

Wenxi Zhai, Xiangdong Zhang

Published:

Abstract:
In this paper, we present exact spherically symmetric Gauss-Bonnet black hole solutions surrounded by a cloud of strings fluid with cosmological constant in

\begin{document}$ D>4 $\end{document}

dimensions. Both charged and uncharged cases are considered. We focus on the de Sitter solutions in the main text and leave the Anti-de Sitter solutions in the appendix. We analyze the features of event horizons and thermodynamic properties of the black hole solutions. The mass, Hawking temperature as well as thermal stability and the phase transitions are discussed. Moreover, the equation of state and critical phenomena associated with these solutions are also explored.

Soft pattern of Rutherford scattering from heavy target mass expansion

Yu Jia, Jia-Yue Zhang

Published:

Abstract:
We investigate the soft behavior of the tree-level Rutherford scattering process. We consider two types of Rutherford scattering, a low-energy massless point-like projectile (say, a spin-

\begin{document}$ {1\over 2} $\end{document}

or spin-

\begin{document}$ 0 $\end{document}

electron) hits a static massive composite target particle carrying various spins (up to spin-

\begin{document}$ 2 $\end{document}

), and a slowly-moving light projectile hits a heavy static composite target. For the first type, the unpolarized cross sections in the laboratory frame are found to exhibit universal forms in the first two orders of

\begin{document}$ 1/M $\end{document}

expansion, yet differ at the next-to-next-to-leading order (though some terms at this order still remain to be universal or depend on the target spin in a definite manner). For the second type, at the lowest order in electron velocity expansion, through all orders in

\begin{document}$ 1/M $\end{document}

, the unpolarized cross section is universal (also not sensitive to the projectile spin). The universality partially breaks down at relative order-

\begin{document}$ v^2/M^2 $\end{document}

, though some terms at this order are still universal or depend on the target spin in a specific manner. We also employ the effective field theory approach to reproduce the soft behavior of the differential cross sections for the target particle being a composite spin-

\begin{document}$ {1\over 2} $\end{document}

fermion.

Just Accepted